I did investigate this a few years ago (prior to JAR-FCL 2). I was told that the UK ATPL(H) was in fact, effectively, an ATPL(H/G): i.e. it covered gyroplanes. You needed to do a gyroplane rating course. Didn't pursue it at the time (I came to my senses??) but it might all have been changed with the advent of JAR. I don't think there are any public transport certified gyroplanes in the UK, but I may well be wrong.